Bone marrow is the major site of blood cell formation and, while at birth it is found within nearly all bones, by adolescence it is located primarily within axial bones (e.g., pelvis and femur). The bone marrow exists in the inner portion of bones, referred to herein as the marrow space, and contains the precursor stem cells that ultimately become red blood cells, white blood cells, and platelets.
Bone marrow aspirations and biopsies are common tests used to evaluate the bone marrow for leukemias and other hematologic disorders, for example. A sampling of the marrow from the marrow space can determine cell number, cell shape, and cell maturation. Special pathologic stains and molecular studies on the marrow specimens can establish certain diagnoses. Sampling of marrow from the marrow space may occur at multiple times during a patient's treatment program to assess progress.
Conventionally, in order to access bone marrow of a patient, the bone must be punctured each time a doctor needs to access the marrow. This is painful for the patient, and imposes a significant burden on the doctor and healthcare resources. There exists a need for an implantable bone marrow access apparatus that can be retained subcutaneously in the bone of a patient throughout the course of treatment to allow repeated access to the bone marrow without requiring repeated bone punctures.